The distribution and properties of DLAs at z

Determining the spatial distribution and intrinsic physical properties of neutral hydrogen on cosmological scales is one of the key goals of next-generation radio surveys. We use the EAGLE galaxy formation simulations to assess the properties of damped Lyman a absorbers (DLAs) that are associated with galaxies and their underlying dark matter haloes between 0 = 10(10)M(circle dot); and the covering fraction of DLAs in the circumgalactic medium (CGM) is enhanced relative to that of the interstellar medium (ISM) with increasing halo mass. Moreover, we find that the mean density of the HI in galaxies increases with increasing stellar mass, while the DLAs in high- and low-halo mass systems have higher column densities than those in galaxies with intermediate halo masses (similar to 10(12) M-circle dot at z = 0). These high-impact CGM DLAs in high-stellar mass systems tend to be metal poor, likely tracing smooth accretion. Overall, our results point to the CGM playing an important role in DLA studies at high redshift (z >= 1). However, their properties are impacted both by numerical resolution and the detailed feedback prescriptions employed in cosmological simulations, particularly that of active galactic nuclei.